The present invention relates to a printer system. More particularly, the invention relates to a print engine for a printer system.
When not in use, inkjet printers contain a predetermined quantity of ink. To inhibit the evaporation of ink through nozzles of the printhead, the printheads must be capped. Ink evaporation can lead to gradual deposition of ink components which can impair nozzle operation.
According to the invention there is provided a print engine for a printer, the print engine including:
a page width printhead, the printhead including an ink-ejecting means and a sealing means surrounding the ink-ejecting means;
a transfer means on to which ink ejected by the printhead is received to be transferred to a sheet of print media, the transfer means being arranged adjacent to the printhead; and
a displacement means for displacing the printhead so that its sealing means is urged into abutment with a surface of the transfer means when the printhead is inoperative to inhibit evaporation of ink from the ink-ejecting means, the displacement means further being operable to draw the printhead into spaced relationship relative to the transfer means when printing is to be effected.
In this specification, unless the context clearly indicates otherwise, the term xe2x80x9cpage width printheadxe2x80x9d is to be understood as a printhead having a printing zone that prints one line at a time on a page, the line being parallel either to a longer edge or a shorter edge of the page. The line is printed as a whole as the page moves past the printhead and the printhead is stationary, i.e. it does not raster.
The ink-ejecting means of the printhead may be a microelectromechanical device having a plurality of inkjet nozzles. The sealing means may be an elastomeric seal surrounding the ink-ejecting means. The sealing means may comprise a plurality of nested ribs surrounding a semi-conductor device defining the inkjet nozzles.
The transfer means may include a transfer roller rotatably mounted adjacent to the printhead so that ink ejected by the printhead is deposited on a surface of the transfer roller. In a preferred embodiment of the invention, at least a surface of the transfer roller is of a wear resistant material which is resistant to pitting, scoring or scratching. Thus, at least the surface of the transfer roller may be of titanium nitride.
The displacement means may include an electromagnetically operable device. The electromagnetically operable device may be a solenoid which, to draw the printhead away from the transfer means, requires a first, higher current and to hold the printhead in spaced relationship relative to the transfer means requires a second, lower current.
The print engine may include an urging means for urging a sheet of print media into contact with the surface of the transfer means. The urging means may either be a pinch roller or, where two print engines are provided for effecting double-sided printing, a transfer roller of an opposed, aligned print engine.
The print engine may also include a cleaning station for cleaning the surface of the transfer means, the cleaning station being arranged intermediate the urging means and the printhead. The cleaning station may include a cleaning element of an absorbent, resiliently flexible material, such as a sponge, and a wiper of a resiliently flexible material, the wiper being arranged intermediate the cleaning element and the printhead. The wiper may be in the form of a strip of rubber.